<s>
eSpeak	B-Language
is	O
a	O
free	B-License
and	I-License
open-source	I-License
,	O
cross-platform	B-Operating_System
,	O
compact	O
,	O
software	O
speech	B-Application
synthesizer	I-Application
.	O
</s>
<s>
eSpeakNG	B-Language
(	O
Next	O
Generation	O
)	O
is	O
a	O
continuation	O
of	O
the	O
original	O
developer	O
's	O
project	O
with	O
more	O
feedback	O
from	O
native	O
speakers	O
.	O
</s>
<s>
Because	O
of	O
its	O
small	O
size	O
and	O
many	O
languages	O
,	O
eSpeakNG	B-Language
is	O
included	O
in	O
NVDA	B-Language
open	O
source	O
screen	O
reader	O
for	O
Windows	B-Application
,	O
as	O
well	O
as	O
Android	O
,	O
Ubuntu	B-Operating_System
and	O
other	O
Linux	B-Application
distributions	O
.	O
</s>
<s>
Its	O
predecessor	O
eSpeak	B-Language
was	O
recommended	O
by	O
Microsoft	O
in	O
2016	O
and	O
was	O
used	O
by	O
Google	B-Application
Translate	I-Application
for	O
27	O
languages	O
in	O
2010	O
;	O
17	O
of	O
these	O
were	O
subsequently	O
replaced	O
by	O
proprietary	O
voices	O
.	O
</s>
<s>
In	O
eSpeakNG	B-Language
's	O
predecessor	O
eSpeak	B-Language
,	O
the	O
initial	O
versions	O
of	O
some	O
languages	O
were	O
based	O
on	O
information	O
found	O
on	O
Wikipedia	O
.	O
</s>
<s>
Most	O
of	O
the	O
people	O
who	O
have	O
helped	O
to	O
improve	O
the	O
various	O
languages	O
are	O
blind	O
users	O
of	O
text-to-speech	B-Application
.	O
</s>
<s>
In	O
1995	O
,	O
Jonathan	O
Duddington	O
released	O
the	O
Speak	O
speech	B-Application
synthesizer	I-Application
for	O
RISC	B-Operating_System
OS	I-Operating_System
computers	O
supporting	O
British	O
English	O
.	O
</s>
<s>
On	O
17	O
February	O
2006	O
,	O
Speak	O
1.05	O
was	O
released	O
under	O
the	O
GPLv2	O
license	O
,	O
initially	O
for	O
Linux	B-Application
,	O
with	O
a	O
Windows	B-Application
SAPI	I-Application
5	I-Application
version	O
added	O
in	O
January	O
2007	O
.	O
</s>
<s>
Development	O
on	O
Speak	O
continued	O
until	O
version	O
1.14	O
,	O
when	O
it	O
was	O
renamed	O
to	O
eSpeak	B-Language
.	O
</s>
<s>
Development	O
of	O
eSpeak	B-Language
continued	O
from	O
1.16	O
(	O
there	O
was	O
not	O
a	O
1.15	O
release	O
)	O
with	O
the	O
addition	O
of	O
an	O
eSpeakEdit	O
program	O
for	O
editing	O
and	O
building	O
the	O
eSpeak	B-Language
voice	O
data	O
.	O
</s>
<s>
These	O
were	O
only	O
available	O
as	O
separate	O
source	O
and	O
binary	O
downloads	O
up	O
to	O
eSpeak	B-Language
1.24	O
.	O
</s>
<s>
The	O
1.24.02	O
version	O
of	O
eSpeak	B-Language
was	O
the	O
first	O
version	O
of	O
eSpeak	B-Language
to	O
be	O
version	O
controlled	O
using	O
subversion	B-Application
,	O
with	O
separate	O
source	O
and	O
binary	O
downloads	O
made	O
available	O
on	O
SourceForge	O
.	O
</s>
<s>
From	O
eSpeak	B-Language
1.27	O
,	O
eSpeak	B-Language
was	O
updated	O
to	O
use	O
the	O
GPLv3	O
license	O
.	O
</s>
<s>
The	O
last	O
official	O
eSpeak	B-Language
release	O
was	O
1.48.04	O
for	O
Windows	B-Application
and	O
Linux	B-Application
,	O
1.47.06	O
for	O
RISC	B-Operating_System
OS	I-Operating_System
and	O
1.45.04	O
for	O
macOS	B-Application
.	O
</s>
<s>
The	O
last	O
development	O
release	O
of	O
eSpeak	B-Language
was	O
1.48.15	O
on	O
16	O
April	O
2015	O
.	O
</s>
<s>
eSpeak	B-Language
uses	O
the	O
Usenet	O
scheme	O
to	O
represent	O
phonemes	B-Language
with	O
ASCII	O
characters	O
.	O
</s>
<s>
On	O
25	O
June	O
2010	O
,	O
Reece	O
Dunn	O
started	O
a	O
fork	B-Application
of	O
eSpeak	B-Language
on	O
GitHub	B-Application
using	O
the	O
1.43.46	O
release	O
.	O
</s>
<s>
This	O
started	O
off	O
as	O
an	O
effort	O
to	O
make	O
it	O
easier	O
to	O
build	O
eSpeak	B-Language
on	O
Linux	B-Application
and	O
other	O
POSIX	O
platforms	O
.	O
</s>
<s>
On	O
4	O
October	O
2015	O
(	O
6	O
months	O
after	O
the	O
1.48.15	O
release	O
of	O
eSpeak	B-Language
)	O
,	O
this	O
fork	B-Application
started	O
diverging	O
more	O
significantly	O
from	O
the	O
original	O
eSpeak	B-Language
.	O
</s>
<s>
On	O
8	O
December	O
2015	O
,	O
there	O
were	O
discussions	O
on	O
the	O
eSpeak	B-Language
mailing	O
list	O
about	O
the	O
lack	O
of	O
activity	O
from	O
Jonathan	O
Duddington	O
over	O
the	O
previous	O
8	O
months	O
from	O
the	O
last	O
eSpeak	B-Language
development	O
release	O
.	O
</s>
<s>
This	O
evolved	O
into	O
discussions	O
of	O
continuing	O
development	O
of	O
eSpeak	B-Language
in	O
Jonathan	O
's	O
absence	O
.	O
</s>
<s>
The	O
result	O
of	O
this	O
was	O
the	O
creation	O
of	O
the	O
espeak-ng	O
(	O
Next	O
Generation	O
)	O
fork	B-Application
,	O
using	O
the	O
GitHub	B-Application
version	O
of	O
eSpeak	B-Language
as	O
the	O
basis	O
for	O
future	O
development	O
.	O
</s>
<s>
On	O
11	O
December	O
2015	O
,	O
the	O
espeak-ng	O
fork	B-Application
was	O
started	O
.	O
</s>
<s>
The	O
first	O
release	O
of	O
espeak-ng	O
was	O
1.49.0	O
on	O
10	O
September	O
2016	O
,	O
containing	O
significant	O
code	O
cleanup	O
,	O
bug	O
fixes	O
,	O
and	O
language	O
updates	O
.	O
</s>
<s>
eSpeakNG	B-Language
can	O
be	O
used	O
as	O
a	O
command-line	O
program	O
,	O
or	O
as	O
a	O
shared	O
library	O
.	O
</s>
<s>
It	O
supports	O
Speech	B-Application
Synthesis	I-Application
Markup	I-Application
Language	I-Application
(	O
SSML	O
)	O
.	O
</s>
<s>
eSpeakNG	B-Language
uses	O
an	O
ASCII	O
representation	O
of	O
phoneme	B-Language
names	O
which	O
is	O
loosely	O
based	O
on	O
the	O
Usenet	O
system	O
.	O
</s>
<s>
For	O
example	O
:	O
espeak-ng	O
-v	O
en	O
"	O
Hello	O
 [  [ w3:ld ]  ] 	O
 "	O
will	O
say	O
in	O
English	O
.	O
</s>
<s>
eSpeakNG	B-Language
can	O
be	O
used	O
as	O
text-to-speech	B-Application
translator	O
in	O
different	O
ways	O
,	O
depending	O
on	O
which	O
text-to-speech	B-Application
translation	O
step	O
user	O
want	O
to	O
use	O
.	O
</s>
<s>
There	O
are	O
many	O
languages	O
(	O
notably	O
English	O
)	O
which	O
do	O
n't	O
have	O
straightforward	O
one-to-one	O
rules	O
between	O
writing	O
and	O
pronunciation	O
;	O
therefore	O
,	O
the	O
first	O
step	O
in	O
text-to-speech	B-Application
generation	O
has	O
to	O
be	O
text-to-phoneme	O
translation	O
.	O
</s>
<s>
input	O
text	O
is	O
translated	O
into	O
pronunciation	O
phonemes	B-Language
(	O
e.g.	O
</s>
<s>
in	O
eSpeakNG	B-Language
format	O
stressed	O
syllable	O
is	O
added	O
using	O
apostrophe	O
:	O
which	O
provides	O
more	O
natural	O
speech	O
:	O
</s>
<s>
If	O
eSpeakNG	B-Language
is	O
used	O
for	O
generation	O
of	O
prosody	O
data	O
only	O
,	O
then	O
prosody	O
data	O
can	O
be	O
used	O
as	O
input	O
for	O
MBROLA	B-Application
diphone	O
voices	O
.	O
</s>
<s>
The	O
eSpeakNG	B-Language
provides	O
two	O
different	O
types	O
of	O
formant	O
speech	B-Application
synthesis	I-Application
using	O
its	O
two	O
different	O
approaches	O
.	O
</s>
<s>
With	O
its	O
own	O
eSpeakNG	B-Language
synthesizer	O
and	O
a	O
Klatt	O
synthesizer	O
:	O
</s>
<s>
The	O
eSpeakNG	B-Language
synthesizer	O
creates	O
voiced	O
speech	O
sounds	O
such	O
as	O
vowels	O
and	O
sonorant	O
consonants	O
by	O
additive	O
synthesis	O
adding	O
together	O
sine	O
waves	O
to	O
make	O
the	O
total	O
sound	O
.	O
</s>
<s>
The	O
Klatt	O
synthesizer	O
mostly	O
uses	O
the	O
same	O
formant	O
data	O
as	O
the	O
eSpeakNG	B-Language
synthesizer	O
.	O
</s>
<s>
For	O
the	O
MBROLA	B-Application
voices	O
,	O
eSpeakNG	B-Language
converts	O
the	O
text	O
to	O
phonemes	B-Language
and	O
associated	O
pitch	O
contours	O
.	O
</s>
<s>
It	O
passes	O
this	O
to	O
the	O
MBROLA	B-Application
program	O
using	O
the	O
PHO	O
file	O
format	O
,	O
capturing	O
the	O
audio	O
created	O
in	O
output	O
by	O
MBROLA	B-Application
.	O
</s>
<s>
That	O
audio	O
is	O
then	O
handled	O
by	O
eSpeakNG	B-Language
.	O
</s>
<s>
eSpeakNG	B-Language
performs	O
text-to-speech	B-Application
synthesis	O
for	O
the	O
following	O
languages	O
:	O
</s>
